At times it may be necessary to interconnect first and second devices via a single wire connection. When devices are connected in this fashion, one device is designated as the host device for controlling the communications between the two devices while the other device is designated as the slave device so as to control traffic on the single wire bus. Host and slave devices interconnected by a single wire require the use of a single wire interface protocol to enable the transmission of data over the single wire between the two devices. Previous systems have used a number of different techniques to transmit information over a single wire. One such system controls transmissions between a host device and a slave device by initially transmitting control information from the host device to the slave device. After transmission of the control information, the host device next drives the signal on the single wire low to indicate the beginning of a transmission period. After a predetermined delay from the start of the transmission period, the data to be transmitted between the host device and the slave device is indicated on the single wire by driving the voltage level on the line high if a logical “1” is being transmitted or maintaining the signal at a low level if a logical “0” is being transmitted. Thus, the time period required to transmit either a logical “1” bit or a logical “0” bit is the same no matter which logical bit is being transmitted since the logical data always resides within a predetermined delay from the initiation of the transmission period.
Digital authentication can be an important part of modern systems. Authentication has uses in communication, transactions and devices. There are often trade-offs in authentication protocols between speed and security. It may be important to have an authentication system that may be performed quickly and still provide adequately secure authentication. Authentication of devises such as a battery are necessary to insure that a correct battery is being used with a particular product. Since battery and associated devices may often times be connected by a single conductor. An authentication process which may be performed over a single wire conductor would be useful.